Effectiveness of the endotracheal tube cuff on the trachea: physical and mechanical aspects

Introduction

The inflation pressure of the endotracheal tube cuff can cause ischemia of the tracheal mucosa at high pressures; thus, it can cause important tracheal morbidity and tracheal microaspiration of the oropharyngeal secretion, or it can even cause pneumonia associated with mechanical ventilation if the pressure of the cuff is insufficient.

Objective

In order to investigate the effectiveness of the RUSCH® 7.5 mm endotracheal tube cuff, this study was designed to investigate the physical and mechanical aspects of the cuff in contact with the trachea.

Methods

For this end, we developed an in vitro experimental model to assess the flow of dye (methylene blue) by the inflated cuff on the wall of the artificial material. We also designed an in vivo study with 12 Large White pigs under endotracheal intubation. We instilled the same dye in the oral cavity of the animals, and we analyzed the presence or not of leakage in the trachea after the region of the cuff after their deaths (animal sacrifice). All cuffs were inflated at the pressure of 30 cmH₂O.

Results

We observed the passage of fluids through the cuff in all in vitro and in vivo experimental models.

Conclusion

We conclude that, as well as several other cuff models in the literature, the RUSCH® 7.5 mm tube cuffs are also not able to completely seal the trachea and thus prevent aspiration of oropharyngeal secretions. Other prevention measures should be taken.     

Neurotrophic factors in women with crack cocaine dependence during early abstinence: the role of early life stress

Background

Neurotrophic factors have been investigated in the pathophysiology of alcohol and drug dependence and have been related to early life stress driving developmental programming of neuroendocrine systems.

Methods

We conducted a follow-up study that aimed to assess the plasma levels of glial cell line–derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin-3 (NT3) and neurotrophin-4/5 (NT4/5) in crack users during 3 weeks of early abstinence in comparison with healthy controls. We performed a comprehensive clinical assessment in female inpatients with crack cocaine dependence (separated into 2 groups: participants with (CSA+) and without (CSA−) a history of childhood sexual abuse) and a group of nonuser control participants.

Results

Our sample included 104 women with crack cocaine dependence and 22 controls; of the women who used crack cocaine, 22 had a history of childhood sexual abuse and 82 did not. The GDNF plasma levels in the CSA+ group increased dramatically during 3 weeks of detoxification. In contrast, those in the CSA− group showed lower and stable levels of GDNF under the same conditions. Compared with the control group, BDNF plasma levels remained elevated and NGF levels were reduced during early abstinence. We found no differences in NT3 and NT4/5 between the patients and controls. However, within-group analyses showed that the CSA+ group exhibited higher levels of NT4/5 than the CSA− group at the end of detoxification.

Limitations

Some of the participants were using neuroleptics, mood stabilizers or antidepressants; our sample included only women; memory bias could not be controlled; and we did not investigate the possible confounding effects of other forms of stress during childhood.

Conclusion

This study supports the association between early life stress and peripheral neurotrophic factor levels in crack cocaine users. During early abstinence, plasmastic GDNF and NT4/5 were the only factors to show changes associated with a history of childhood sexual abuse.     

Mortality related to coagulase-negative staphylococcal bacteremia in febrile neutropenia: A cohort study

BACKGROUND:

Coagulase-negative staphylococci (CoNS) are currently the most common isolates recovered from the blood of patients with cancer and febrile neutropenia (FN).

OBJECTIVES:

To assess the mortality associated with bloodstream infections (BSIs) caused by CoNS in cancer patients with FN.

METHODS:

A prospective cohort study was conducted in a single tertiary hospital from October 2009 to August 2011. Follow-ups were performed on all of the adult patients who were admitted to the hematology ward with cancer and FN. Bacteremia caused by CoNS was defined as two positive results of two independent cultures. Twenty-eight days after the onset of FN, the mortality rates of the patients with BSIs caused by CoNS were compared with those of patients with BSIs caused by other pathogens.

RESULTS:

A total of 169 subjects were evaluated. During the study period, 78 patients with BSIs were documented. Twenty-three BSIs (29.4%) were a result of CoNS. CoNS-induced bacteremia resulted in lower 28-day mortality compared with bacteremia caused by other pathogens (4.3% versus 32.7%; log-rank P=0.009). In a Cox proportional hazards regression analysis, BSIs caused by CoNS were independently associated with lower mortality (HR 0.09 [95% CI 0.01 to 0.74]).

CONCLUSIONS:

In adult patients with cancer and FN, BSIs caused by CoNS were associated with lower mortality compared with BSIs caused by other pathogens.     

Long-term decrease in Na,K-ATPase activity after pilocarpine-induced status epilepticus is associated with nitration of its alpha subunit

Temporal lobe epilepsy (TLE) is the most common type of epilepsy with about one third of TLE patients being refractory to antiepileptic drugs. Knowledge about the mechanisms underlying seizure activity is fundamental to the discovery of new drug targets. Brain Na⁺,K⁺-ATPase activity contributes to the maintenance of the electrochemical gradients underlying neuronal resting and action potentials as well as the uptake and release of neurotransmitters. In the present study we tested the hypothesis that decreased Na⁺,K⁺-ATPase activity is associated with changes in the alpha subunit phosphorylation and/or redox state. Activity of Na⁺,K⁺-ATPase decreased in the hippocampus of C57BL/6 mice 60 days after pilocarpine-induced status epilepticus (SE). In addition, the Michaelis–Menten constant for ATP of α2/3 isoforms increased at the same time point. Nitration of the α subunit may underlie decreased Na⁺,K⁺-ATPase activity, however no changes in expression or phosphorylation state at Ser⁹⁴³ were found. Further studies are necessary define the potential of nitrated Na⁺,K⁺-ATPase as a new therapeutic target for seizure disorders.     

ATP P2Y1 receptors control cognitive deficits and neurotoxicity but not glial modifications induced by brain ischemia in mice

ATP is a pleiotropic cell‐to‐cell signaling molecule in the brain that functions through activation of the P2 receptors (P2R), encompassing ionotropic P2XR or metabotropic P2YR. Noxious brain insults increase the extracellular levels of ATP and previous studies have implicated different P2R, namely P2Y1R, in the control of ischemic brain damage, but it remains to be defined if P2Y1R antagonists also alleviate the behavioral impairments associated with brain ischemia. Furthermore, as P2Y1R can control neuronal and glial functions, we explored if P2Y1R antagonist‐mediated protection would mainly involve neuronal and/or glial processes. Adult male mice subject to permanent middle cerebral artery occlusion (pMCAO) displayed an infarcted cortical area (2,3,5‐triphenyltetrazolium chloride staining), decreased neurological score with decreased working and reference memory performance (Y‐maze, object recognition and aversive memory), accompanied by neuronal damage (FluoroJade C), astrogliosis (glial fibrillary acidic protein) and microgliosis (CD11b). All of these changes were attenuated by intracerebroventricular pre‐treatment (10 min before pMCAO) with the generic P2R antagonist 4‐[(E)‐{4‐formyl‐5‐hydroxy‐6‐methyl‐3‐[(phosphono‐oxy)methyl]pyridin‐2‐yl}diazenyl]benzene‐1,3‐disulfonic acid (PPADS, 0.5–1.0 nmol/μL). In contrast, the selective P2Y1R antagonist (1R*,2S*)‐4‐[2‐Iodo‐6‐(methylamino)‐9H‐purin‐9‐yl]‐2‐(phosphono‐oxy)bicycle[3.1.0] hexane‐1‐methanol dihydrogen phosphate ester (MRS2500, 1.0–2.0 nmol/μL) afforded equivalent behavioral benefits but only prevented neuronal damage but not astrogliosis or microgliosis upon pMCAO. These results indicated that P2Y1R‐associated neuroprotection mainly occurred through neuronal mechanisms, whereas other P2R were also involved in the control of astrocytic reactivity upon brain injury.     

Bevacizumab versus triamcinolone for persistent diabetic macular edema: a randomized clinical trial

Graefe's Archive for Clinical and Experimental Ophthalmology - To evaluate 24-week visual acuity and anatomic outcomes of two “pro re nata” (prn) treatment strategies (intravitreal...     

Lack of correlation between tubular dentine cement penetration, adhesiveness and leakage in roots filled with gutta percha and an endodontic cement based on epoxy amine resin

Objective

To analyze possible correlations among tubular dentine cement penetration, adhesiveness and apical leakage in fillings performed with gutta percha and an endodontic cement based on epoxy amine resin.

Material and Methods

Sixty similar, extracted human mandibular central incisors were irrigated, instrumented and filled following the same protocol. First, apical leakage was quantified by fluid filtration tests. Then, these same specimens were sectioned for analysis of tubular dentine cement penetration and the middle thirds were submitted to push-out tests to analyze the adhesiveness of the fillings.

Results

In brief, the means and standard deviations with a confidence interval of 95% were as follows: tubular dentine cement penetration (8.875±4.540), adhesiveness (4.441±2.683) and apical leakage (0.318±0.215). The data were confronted using the Pearson''s test (P>0.05), and it was possible to prove that there was no correlation between (1) tubular dentine cement penetration and apical leakage (r²: 0.08276), (2) tubular dentine cement penetration and adhesiveness (r²: -0.2412) and (3) adhesiveness and apical leakage (r²: 0.1340).

Conclusion

After analysis of these data, it could be observed that there exists no correlation among the variables analyzed in this study.